A flushing apparatus for toilets common in the United States involves a reseating flush valve the holds a minimized volume of supply water in a tank from which it is suddenly released into the toilet bowl. And, a float valve is responsive to the water level in the tank to replace the water level, operating automatically and separately from the flush valve that is manually operated by movement of a flush handle or lever that is turned to lift the flush valve. A detrimental feature of this common system is that the flush valve tends to and eventually leaks, resulting in continued water waste.
Another flushing apparatus, common in the United Kingdom, involves a syphon tube having its suction leg depending into the supply tank so as to be partially filled with water, and its discharge leg normally empty of water and opening into the toilet bowl, and operated by means of a primer pump that is manually actuated to fill the syphon legs and thereby initiating syphoning. The said primer pump operates as a water lifting means in the suction leg of the syphon, and the advantage of this syphon system is that there can be no leakage from the supply tank through the inactive syphon.
A feature of state of the art toilets is the low volume of storage tank water required for flushing, this minimal flush water requirement being, characterized by low level water storage the supply tank, a typical condition in the United States, and a mandatory level condition in the United Kingdom. Accordingly, difficulty is experienced in lifting supply tank water sufficiently to initiate the syphon function necessary for flushing. In the United Kingdom there is a requirement that there be a "Warning. Pipe" and more particularly an overflow pipe placed in the supply tank a substantial distance below the bridge of the syphon. This distance is specified as 64 mm a requirement which has an adverse effect on the primer tank activated syphon of the present invention. In this respect, it has been discovered that indiscriminately rapid discharge of primer tank water is or can be ineffective to start the syphon function. Accordingly, it in an object of this invention to discriminately discharge primer tank water so that initiation of the syphon function is assured when subjected to said low water level conditions.
It has been discovered by a reduction to practice of the present invention that suction leg water of the syphon does not lift over the syphon bridge when the primer tank water discharges too quickly, due to the related inertia of water to be lifted in the suction leg. Time is of the essence, in that time for induction of water up and over the syphon bridge is a fundamental requirement. Accordingly, it is an object of this invention to retard the drop and/or discharge of water in and from the primer tank and over the jet opening that initiates the syphon function. In practice, this is accomplished by closing the primer tank to outside atmosphere and restricting the admission of air thereto, whereby a partial vacuum is established over the primer tank water so as to retard its drop and prolong its effective discharge. This air inlet restriction is also necessary as a vent that enables filling of the primer tank. Functionally, as the primer tank water drops, it sucks air through a restriction and creats a negative pressure within the primer tank and thereby retards the drop and discharge of water therefrom. This increases the effective time interval that draws suction leg water up and over the syphon bridge. This unique air restriction is adjustable.
In view of the foregoing, it is an object of this invention to employ the aforesaid syphon tube fush principle of operation to the exclusion of pump means, and replacing the aforesaid pump-type primer means with a controlled syphon primer means activated by opening of the flush valve, all in combination with an otherwise conventional United States or United Kingdom state of the art toilet.
The syphon principle of operation is superior with respect to the conservation or water, in that there can be no continuous leakage therethrough when its discharge leg is empty or water. And, only when the discharge leg is primed does water flow therethrough. On the contrary, the conventional flush valve principle of operation is prone to continuous leakage from the water supply tank and through the flush tube, due to deterioration of either the valve seat or valve ball.
It is to be understood that the water supply tank is refilled after each flushing operation, or incomplete flushing operation, by means of a conventional and accepted water level responive valve means from a water supply service pipe. In practice, a float controlled valve returns the tank water level to a predetermined point.
The syphon principle of operation is characterized by two conditions, a passive condition wherein the discharge leg is closed to the flush pipe by the flush valve and the primer tank is in open communication with and to fill the discharge leg with water up to the syphon bridge and with a transfer passage over the bridge and between the two syphon legs that are empty and vented to outside atmosphere, and a functioning condition wherein the discharge leg is opened to the flush pipe by lifting the flush valve, a float, and opening the primer tank for controlled discharge of water over a jet opening of the discharge leg and into the flush pipe and inherently closing the atmosphere vent to said transfer chamber.
The flush valve closes the discharge leg below the bottom opening of the primer tank, the bottoms of the primer tank and discharge leg being separated by the jet opening and in open communicaton. In order to achieve said functioning condition, priming of the sypon is equired for filling the otherwise empty transfere passage with water, whereupon syphoning action is initiated and continues to occur.
The apparatus herein disclosed is characterized by the atmospheric closure of the transfer passage in the flush mode, which is a prerequisite to successful flushing, and to this end it is an object of this invention to provide vent control means by which the transfer passage is closed to atmosphere in the flush mode, said vent being open to atmosphere in the passive mode in order to enable filling of the two syphon legs.